originalKey.Diff(targetKey) or originalNote.Diff(targetNote) returns nearet +/- semitones

[charneykaye]

Key

originalKey := key.Of("Db minor")
targetKey := key.Of("F# major")
shiftSemitones := originalKey.Diff(targetKey) // equals +5

Which implements Note:

originalNote := note.Fs
targetNote := note.Cs
shiftSemitones := originalNote.Diff(targetNote) // equals -5